JPH0366013A - Composite thin film magnetic head - Google Patents

Abstract

PURPOSE:To carry out good recording and reproduction by specifying the arrangement of the first to third upper magnetic layers constituting the upper magnetic layer and allowing the recording track width and reproducing track width to differ from each other. CONSTITUTION:The first upper magnetic layer 6 has a width identical to the reproducing track width TR. The upper magnetic layer 7 is formed on both sides of the magnetic layer 6 in its cross direction with a space 9 in between. The third upper magnetic layer 8 thinner than the magnetic layers 6 and 7 is formed in the space 9. Accordingly, the recording track width TW is equal to the sum of the widths of the magnetic layers 6-8, and the reproducing track width TR is equal to the width of the magnetic layer 6. Since the recording track width is different from the reproducing track width, the reproducing output is not decreased even if the traveling of a recording medium in recording deviated from that in reproduction. In addition, as the magnetic layer 8 is thin, reproduction is carried out at a low crosstalk level.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a thin film magnetic head used in a magnetic recording/reproducing device.

2. Description of the Related Art In recent years, thin film magnetic heads have been attracting attention in response to higher recording densities and higher data transfer speeds in magnetic recording and reproducing devices.

A conventional thin film magnetic head is shown in FIG. 4 and 513iU.

FIG. 4 shows a wire-wound thin film magnetic head, in which a lower magnetic N22 made of a soft magnetic material is laminated on a substrate 21, and a gap layer 23 made of an insulating layer with a predetermined thickness is disposed on the lower magnetic layer 22.
A conductive coil 25 is formed so as to be embedded in the insulation N24, and an upper magnetic layer 26 made of a soft magnetic material is formed.During recording, the conductive coil 25 is formed.
A signal current is applied to the recording medium by the magnetic field generated in the gap, and during reproduction, the signal magnetic field on the recording medium flowing from the gap is transferred to the conductive coil 25.
Detected by.

FIG. 5 shows a magnetoresistive thin film magnetic head that utilizes the magnetoresistive effect, and consists of a gap 33, a front yoke 35, a magnetoresistive element 34, a rear yoke 36, and a lower magnetic layer 32 on a substrate 31. A magnetoresistive element 3 constitutes a circuit and converts the signal magnetic field on the recording medium flowing from the gap into a magnetoresistive element 3.
Detected by 4.

Problems to be Solved by the Invention In order to increase the reproduction output of the above-mentioned conventional wire-wound thin film magnetic head, it is necessary to increase the number of windings or increase the relative speed with the recording medium. Due to the structure of the magnetic recording/reproducing device, if the relative speed with respect to the recording medium is low, the number of windings must be further increased. In this regard, when reproducing using a magnetoresistive thin-film magnetic head, a constant reproduction output can be obtained regardless of the running speed of the medium. There are also magnetic recording and reproducing devices that use thin-film magnetic heads.

However, when using dedicated heads for recording and reproduction, it is necessary to install each head in a magnetic recording/reproducing device with the gap planes parallel to each other and the center positions in the track width direction aligned, resulting in narrower tracks. In the case of a head compatible with this, there was a problem in that it was difficult to install.

In order to solve these problems, a composite thin film magnetic head combining a wire-wound type and a magnetoresistive type as shown in Fig. 6 has been proposed (Japanese Patent Application Laid-Open No. 48116/1983).
. However, this composite thin film magnetic head cannot achieve good recording and reproduction if the track widths during recording and reproduction are the same and the running accuracy of the recording medium is poor. This point will be explained below.

If the track width of the composite thin film magnetic head is T and the running accuracy of the recording medium is ±a, then the running deviation during recording and playback is at most 2a, and the effective playback track width is (T1-28).
Therefore, there was a problem that the reproduction output decreased.

The present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to provide a composite thin-film magnetic head that performs good magnetic recording and reproduction.

Means for Solving the Problems To achieve this object, a composite thin film magnetic head of the present invention includes a lower magnetic layer, an upper magnetic layer, and a conductive coil, and the upper magnetic layer has a width equal to the reproduction track width. a first upper magnetic layer, a part of which is replaced with a magnetoresistive element; and a second upper magnetic layer, which is located on both sides of the first upper magnetic layer in the track width direction and is spaced apart from the first upper magnetic layer. The magnetic layer and the film thickness are as described above. a third upper magnetic layer smaller than the second upper magnetic layer and formed at least at a portion in contact with the recording medium within a gap between the first upper magnetic layer and the second upper magnetic layer; the width of the first upper magnetic layer and the width of the second upper magnetic layer;
The sum of the width of the upper magnetic layer and the width of the third upper magnetic layer is made equal to the recording track width.

Effect With the above configuration, the composite thin film magnetic head of the present invention can make the recording track width and the reproduction track width different, and thereby, even if there is a deviation in the running of the recording medium during recording and reproduction, the reproduction can be performed. Output does not decrease.

EXAMPLE A composite thin film magnetic head according to a first example of the present invention will be described below with reference to FIG.

FIG. 1(a) is a plan view of a composite thin film magnetic head in the first embodiment, and FIG. 1(b) is A--A in FIG. 1(a).
A sectional view and FIG. 1(C) are front views of the composite thin film magnetic head in the same embodiment.

The composite thin film magnetic head in the first embodiment has a lower magnetic layer 2 made of a soft magnetic material formed on a non-magnetic substrate 1 so as to have the same width as the recording track width, and an insulating layer formed on the lower magnetic layer 2 having the same width as the recording track width. Naru Gap W! After I3 is formed and the conductive coil 4 is formed, the magnetoresistive element 5 is inserted through the insulating layer.
is formed, and the first upper magnetic 1! F6 and a second upper magnetic layer N7 are formed. First upper magnetic layer 6
A magnetic circuit is formed by winding the conductive coil 4 by the gap layer 3 and the lower magnetic layer 2 via the magnetoresistive element 5, and the second upper magnetic layer M7 connects the first upper magnetic layer 6. They are formed at intervals 9 on both sides in the track width direction, and the gap layer 3 and the lower magnetic layer 2 form a magnetic circuit around which the conductive coil 4 is wound.

The third upper magnetic layer 8 has a thickness smaller than that of the first upper magnetic layer 6 and the second upper magnetic layer 7, and is within the distance 9 between the first upper magnetic layer 6 and the second upper magnetic layer 1m17. It is formed in a portion of the first upper magnetic layer 6 extending from the recording medium sliding surface to the magnetoresistive element 5.

Further, in the magnetoresistive element 5, the electrode 10 is formed so that an effective area is set so as to reproduce the signal magnetic field from the recording medium guided by the first upper magnetic layer 6.

Next, the operation will be explained. During recording, a recording current is applied to the conductive coil 4, and the resulting recording magnetic field is transmitted from a magnetic circuit consisting of the first upper magnetic WI 6 and the lower magnetic layer 2, the second upper magnetic layer 7, and the lower magnetic layer 2. The information is guided to the gap by a magnetic circuit and recorded on a storage medium (not shown). Since the third upper magnetic layer 8 has a small film thickness, the magnetic resistance becomes large, but since the signal magnetic field during recording is large, the signal magnetic field is also applied to the third upper magnetic layer 8. The light flows in from the second upper magnetic layer N7 and is also recorded in the third upper magnetic layer 8.

The recording pattern at this time has a width T, which is the sum of the width of the first upper magnetic layer 60, the width of the second upper magnetic layer 7, and the width of the third upper magnetic layer 8.

During reproduction, a signal magnetic field from the recording medium is guided to the magnetoresistive element 5 by the first upper magnetic layer 6, reproduction is performed, and the width of the first upper magnetic layer 6 becomes the reproduction track radiation TR.

The head is configured such that the recording track width T, , and the reproduction track width TR are T, = T, +2a, assuming the running accuracy of the recording medium as ±a, and the recording track width T, . Even if the running deviation is 2a at maximum, the reproduced track is within the recording track, and furthermore, as described above, the inside of the recording track is completely recorded, so the reproduced signal does not deteriorate.

When the second upper magnetic ff 117 invades an adjacent track due to running deviation, the signal magnetic field of the adjacent track flows into the second upper magnetic layer 7, but the film thickness of the third upper magnetic layer 8 is The signal magnetic field of the adjacent track flowing into the second upper magnetic layer 7 is difficult to flow into the first upper magnetic layer 6 via the third upper magnetic layer 7 due to its large magnetic resistance. Therefore, since the signal magnetic field of the adjacent track does not flow into the magnetoresistive element 5, good reproduction with low crosstalk is performed.

Next, a second embodiment will be described using FIGS. 2 and 3. FIG. 2(a) is a plan view of a composite thin film magnetic head according to the second embodiment, FIG. 2(b) is a front view,
3(a) is a sectional view taken along line BB in FIG. 2, and FIG. 3(b) is a sectional view taken along line CC in FIG. In FIGS. 2 and 3, the same components as in FIG. 1 are designated by the same reference numerals, and their explanations will be omitted.

The second upper magnetic layer 17 in the second embodiment is formed on both sides of the first upper magnetic layer 6 in the track width direction with a gap 19 therebetween, and is located at a portion where the magnetoresistive element 5 is formed. Similar to the first upper magnetic layer 6, a cutout is made at a position adjacent to the first upper magnetic layer 6. The second upper magnetic layer 17, the gap layer 3, and the lower magnetic layer 2 form a magnetic circuit around which the conductive coil 4 is wound.

The third upper magnetic layer 18 has a thickness smaller than that of the first upper magnetic layer 6 and the second upper magnetic layer I'l117, and is within the distance 19 between the first upper magnetic layer 6 and the second upper magnetic layer 17. It is formed in the portion extending from the recording medium sliding surface of the first upper magnetic layer 116 to the magnetoresistive element 5.

The operations during recording and reproduction are the same as those in the first embodiment, so the explanation will be omitted. The recording pattern during recording is width T1
1, which is the sum of the width of the first upper magnetic layer 6, the width of the second upper magnetic layer 11J17, and the width of the third upper magnetic logging layer 18, the recording track width T, and the reproduction track cap. 3 is
When the running accuracy of the recording medium is ±a, T, =TR+2
The structure of the head so as to be a is the same as in the first embodiment.

Even if the running deviation of the recording medium during recording and playback reaches the maximum of 28, the playback track remains within the recording track.
There is no reduction in the reproduced signal.

Furthermore, when the second upper magnetic field N17 invades an adjacent track due to running deviation, the signal magnetic field of the adjacent track is changed to the second upper magnetic field 1! ! However, since the magnetic resistance of the third upper magnetic field flJ8 is large, the signal magnetic field does not flow into the magnetoresistive element 5, and good reproduction with low crosstalk is performed. This is similar to the embodiment. Furthermore, the second upper magnetic field 1'! 117 is the first
As with the upper magnetic layer N6, a part of it is cut out, so that a magnetic circuit consisting of the lower magnetic layer 112 and the first upper magnetic layer 6 and a magnetic circuit consisting of the lower magnetic layer IW2 and the second upper magnetic layer 17 are formed. Since the circuits have the same configuration during recording, there is an effect that recording can be performed with the same recording efficiency.

In addition, 1. In the second embodiment, the third upper magnetic N
8 was formed in a portion of the first upper magnetic layer 1w6 extending from the recording medium sliding surface to the magnetoresistive element 5 within the interval between the first upper magnetic layer 6 and the second upper magnetic layer 7. The above-mentioned effects can be obtained if the upper magnetic layer 8 is formed at least in the portion that comes into contact with the recording medium.

Although different types of magnetic materials may be used for the first upper magnetic layer 6, the second upper magnetic layer 7, and the third upper magnetic layer 8, the first. The same soft magnetic material was used for the first upper magnetic layer, the second upper magnetic layer, and the third upper magnetic layer in the second example. This has the effect of simplifying the process.

Also, 1st. In the second embodiment, the number of turns of the conductive coil 4 is one turn, but it is also possible to use a plurality of turns to reduce the recording current. Further, the conductive coil 4 is also used as a coil for applying a bias magnetic field to the magnetoresistive element 5 during reproduction.

Effects of the Invention As described above, the composite thin film magnetic head of the present invention includes a lower magnetic layer, an upper magnetic layer, and a conductive coil, and the upper magnetic layer has the same width as the reproduction track 1, and a portion thereof a first upper magnetic layer in which the magnetoresistive element is substituted with a magnetoresistive element;
a second upper magnetic layer located on both sides of the upper magnetic layer in the track width direction and formed at intervals;
a third upper magnetic layer, which is smaller than the second upper magnetic layer and is formed at least in a portion where the recording medium contacts, within a gap between the first upper magnetic layer and the second upper magnetic layer; Since the sum of the width of the first upper magnetic layer, the width of the second upper magnetic layer, and the width of the third upper magnetic layer is the same as the recording track width, the recording Assuming that the running accuracy of the medium is ±a, even if the running deviation of the recording medium during recording and playback is at most 2a, the playback track remains within the recording track, and the third upper magnetic layer has a film thickness of Since the magnetic resistance is small, the magnetic resistance becomes large, but since the signal magnetic field during recording is large, the signal magnetic field also flows into the third upper magnetic layer from the first upper magnetic layer and the second upper magnetic layer, and the third upper magnetic layer Since recording is also performed on the layer, recording is completed in the recording track, so the reproduced signal does not deteriorate.

Furthermore, when the second upper magnetic layer enters an adjacent track due to running deviation, the signal magnetic field of the adjacent track flows into the second upper magnetic layer, but the third upper magnetic layer is more sensitive than the second upper magnetic layer. Because the film thickness is small, the magnetic resistance increases,
The signal magnetic field of the adjacent track is transmitted through the third upper magnetic layer to -
Since it is difficult for the magnetic flux to flow into the upper magnetic layer 82 and does not flow into the magnetoresistive element, it is possible to perform good reproduction with low crosstalk.

By cutting out a part of the second upper magnetic layer, the structure of the magnetic circuit becomes the same as that of the first upper magnetic layer, so that recording can be performed with the same efficiency.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1(a) is a plan view of a composite thin film magnetic head according to a first embodiment of the present invention, FIG. 1(b) is a sectional view taken along the line AA on the actual flow side, FIG. 1(C) is a front view of the same embodiment, FIG. 2(a) is a plan view of a composite thin film magnetic head in the second embodiment of the present invention, and FIG. 2(b) is a front view of the same embodiment. The front view, FIG. 3(a) is B-8 in the same embodiment.
3(b) is a C-C sectional view of the same embodiment, FIG. 4 is a sectional view of a conventional wire-wound thin film magnetic head, and FIG. 5 is another conventional magnetoresistive thin film magnetic head. A cross-sectional view of
FIG. 6 is a sectional view of another conventional composite thin film magnetic head. DESCRIPTION OF SYMBOLS 1...Substrate, 2...Lower magnetic layer, 3...
Gap layer, 4... Conductive coil, 5... Magnetoresistive element, 6... First upper magnetic layer, 7.
...Second upper magnetic layer, 8.18...Third upper magnetic layer, 9.19... Spacing, 10... Electrode.

Claims (3)

[Claims] (1) A thin-film magnetic head comprising a lower magnetic layer, an upper magnetic layer, and a conductive coil, wherein the upper magnetic layer has the same width as the reproduction track width, and a part of the upper magnetic layer is replaced with a magnetoresistive element. a first upper magnetic layer having a thickness equal to that of the first and second upper magnetic layers; a third upper magnetic layer smaller than the upper magnetic layer of the first upper magnetic layer and formed at least at a portion in contact with the recording medium within a distance between the first upper magnetic layer and the second upper magnetic layer; A composite thin film magnetism characterized in that the sum of the width of the first upper magnetic layer, the width of the second upper magnetic layer, and the width of the third upper magnetic layer is the same as the recording track width. head. (2) The composite according to claim 1, wherein the second upper magnetic layer is cut out at the same location where a part of the first upper magnetic layer is replaced with the magnetoresistive element. type thin film magnetic head. (3) The composite thin film magnetic head according to claim 1 or 2, wherein the first, second, and third upper magnetic layers are made of the same soft magnetic material.